Series-to-parallel damper assembly including two flanges

ABSTRACT

A damper assembly for a torque converter is provided. The damper assembly includes a first cover plate; a second cover plate, the first cover plate and second cover plate supporting springs therebetween; a first flange between the first cover plate and the second cover plate; and a second flange between the first cover plate and the second plate, the first flange and second flange being arranged with respect to the first and second cover plates and the springs such that the springs transition during operation of the damper assembly from initially operating in series to operating in parallel.

This claims the benefit to U.S. Provisional Patent Application No.61/881,796, filed on Sep. 24, 2013, which is hereby incorporated byreference herein.

The present disclosure relates generally to torque converters and morespecifically to damper assemblies for torque converters.

BACKGROUND

U.S. Pat. No. 7,658,679 discloses a series-parallel damper assembly.

SUMMARY OF THE INVENTION

A damper assembly for a torque converter is provided. The damperassembly includes a first cover plate; a second cover plate, the firstcover plate and second cover plate supporting springs therebetween; afirst flange between the first cover plate and the second cover plate;and a second flange between the first cover plate and the second plate,the first flange and second flange being arranged with respect to thefirst and second cover plates and the springs such that the springstransition during operation of the damper assembly from initiallyoperating in series to operating in parallel.

A torque converter is also provided. The torque converter includes thedamper assembly and a turbine connected to the damper assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described below by reference to the followingdrawings, in which:

FIG. 1 shows cross-sectional side view of a torque converter for a motorvehicle drive train including a damper assembly in accordance with anembodiment of the present invention;

FIGS. 2 a and 2 b are exploded perspective views of the damper assembly;

FIGS. 3 a to 3 d each show two views illustrating the operation of thedamper assembly; and

FIG. 4 shows a damper assembly in accordance with another embodiment ofthe present invention.

DETAILED DESCRIPTION

The present disclosure provides an embodiment of a multi-stage damperwhich, when compared to a conventional damper using the same springs andoverall envelope, is capable of providing the same capacity whileproviding a multi-stage design with greater overall travel and reducedrates. Such conventional series to parallel dampers are more complex,expensive and space consuming. By adding a second flange to a firstflange, the multi-stage damper creates two dampers within a singleenvelope, allowing the first and second flanges to create two to threeprimary spring stages, initially working in series and finallytransitioning to parallel operation.

FIG. 1 shows cross-sectional side view of a torque converter 10 for amotor vehicle drive train including a damper assembly 12 in accordancewith an embodiment of the present invention. Torque converter 10includes a cover 14 including a front cover 16 for connecting to acrankshaft of an internal combustion engine and a rear cover 18 forminga shell 20 of an impeller 22. Impeller shell 20 is nonrotatably fixed toa hub 24. Torque converter 10 also includes a turbine 26 that isconnected to damper assembly 12 and a lockup clutch 28 for rotationallyconnecting damper assembly 12 with front cover 16. Lockup clutch 28includes a piston 29 that is axially movable toward and away from frontcover 16 to rotationally engage damper assembly 12 with and rotationallydisengage damper assembly 12 from front cover 16. Lockup clutch 28 isrotationally coupled to damper assembly 12. More specifically, piston 29of lockup clutch 28 is rotationally connected to a second flange 38 ofdamper assembly 12.

Damper assembly 12 is disposed in an envelope or space 30 formed betweenturbine 26 and front cover 16. Damper assembly 12 includes a first coverplate 32, a second cover plate 34 connected to first cover plate 32 andalso connected to turbine 26, and a first flange 36 and a second flange38 between cover plates 32, 34. In this embodiment, cover plates 32, 34are riveted together by rivets 35. Damper assembly 12 includes twospring sets, each including a least one spring. In this embodiment,springs sets include a first spring set including two springs 44 and asecond spring set including two springs 46. Springs 44, 46 are heldaxially between cover plates 32, 34 at the same radial distance suchthat springs 44, 46 limit the rotation of first flange 36 and secondflange 38 with respect to cover plates 32, 34 by circumferentiallycontacting circumference contact surfaces 66 a, 66 b, 67 a, 67 b offlange 36 and contact surfaces 68 a, 68 b, 69 a, 69 b of flange 38 (seeFIGS. 2 a, 2 b, 3 a to 3 d).

First flange 36 includes a substantially flat plate portion 52 and a hubportion 54 protruding axially from plate portion 52. Hub portion 54 isnonrotatably connected to a rotatable input shaft 56 of a transmission,which rotates radially inside of impeller hub 24 about axis A. Secondflange 38 is positioned on hub portion 54 such that second flange 38 maymove rotationally with respect to first flange 36, as limited by springs44, 46.

FIGS. 2 a and 2 b are exploded perspectives view of damper assembly 12.The only difference between FIGS. 2 a and 2 b is that springs 44, 46 areshown in different places to fully illustrate damper assembly 12, andhub portion 54 is disconnected from and below plate portion 52 of firstflange 36. As noted above, damper assembly 12 includes two spring setsincluding respective springs 44, 46, which alternate circumferentiallyabout axis A. Each cover plate 32, 34 includes four respective slotsformed therein - cover plate 32 includes two slots 58, each forreceiving one of springs 44, and two slots 59, each for receiving one ofsprings 46; while cover plate 34 includes two slots 60, each forreceiving one of springs 44, and two slots 61, each for receiving one ofsprings 46. Slots 58 are each defined in cover plate 32 by tworespective circumferential contact surfaces 58 a, 58 b; slots 59 areeach defined in cover plate 32 by two respective circumferential contactsurfaces 59 a, 59 b; slots 60 are each defined in cover plate 34 by tworespective circumferential contact surfaces 60 a, 60 b; and slots 61 areeach defined in cover plate 34 by two respective circumferential contactsurfaces 61 a, 61 b. Slots 58, 59, 60, 61 may come in and out of contactwith corresponding ends 44 a, 44 b of springs 44 and corresponding ends46 a, 46 b of springs 46 during operation of torque converter 10, asfurther described below with respect to FIGS. 3 a to 3 d. In thisembodiment, slots 58, 60 are all of the same length and slots 59, 61 areall of the same length. Slots 58, 60 may be a different length than orthe same length as slots 59, 61.

First flange 36 includes four slots—two slots 66 of a first length forreceiving springs 46 and two slots 67 of a second length which issmaller than the first length for receiving springs 44—and second flange38 also includes four slots—two slots 68 of a third length for receivingsprings 44 and two slots 69 of a fourth length smaller than the thirdlength for receiving springs 46. Each slot 66 includes two contactsurfaces 66 a, 66 b for contacting ends 46 a, 46 b, respectively, ofsprings 46 and each slot 67 includes two contact surfaces 67 a, 67 b forcontacting ends 44 a, 44 b, respectively, of springs 44. Similarly, eachslot 68 includes two contact surfaces 68 a, 68 b for contacting ends 44a, 44 b, respectively, of springs 44 and each slot 69 includes twocontact surfaces 69 a, 69 b for contacting ends 46 a, 46 b,respectively, of springs 46. Second flange 38 also includes four slots70 radially outside of slots 68, 69, through which rivets 35 connectingcover plates 32, 34 to each other pass. Slots 70 are of a length suchthat rivets 35 can slide circumferentially in slots 70 as second flange38 rotates relative to cover plates 32, 34. A radial outer surface ofsecond flange 38 further includes indentations 72 therein for radiallyengaging piston 29. The radial outer surface of second flange 38 extendsradially outside of cover plates 32, 34. In this embodiment, slots 67are of the same length as slots 58, 60 and slots 69 are of the samelength as slots 59, 61. Slots 66 may be a different length than or thesame length as slots 68.

FIGS. 3 a to 3 d each show two views illustrating the operation ofdamper assembly 12. The view of the left is a plan view (springs 44, 46are omitted, but are identified by their reference numbers 44, 46 andtheir effect is taken into consideration) of flanges 36, 38 and firstcover plate 32 (both cover plates 32, 34 have the same alignment as eachother throughout FIGS. 3 a to 3 d; accordingly, all discussion below ofplate 32 also applies to plate 34) and the view on right is a schematicview illustrating movement and compression of one of springs 44 and oneof springs 46 in relation to cover plates 32, 34 and flanges 36, 38.

FIG. 3 a shows damper assembly 12 in a 0° windup condition. In thiscondition, first ends 44 a and second ends 44 b of springs 44 are incontact with both contact surfaces 58 a, 58 b of both slots 58 of coverplate 32 (and both contact surfaces 60 a, 60 b of both slots 60 of coverplate 34); first ends 44 a and second ends 44 b of springs 44 are incontact with both of the contact surfaces 67 a, 67 b of both slots 67 infirst flange 36; and first ends 44 a and second ends 44 b of springs 44are spaced away from both of contact surfaces 68 a, 68 b of slots 68 insecond flange 38. Also, first ends 46 a and second ends 46 b of springs46 are in contact with both contact surfaces 59 a, 59 b of both slots 59of cover plate 32 (and both contact surfaces 61 a, 61 b of both slots 61of cover plate 34); first ends 46 a and second ends 46 b of springs 46are in contact with both of the contact surfaces 69 a, 69 b of slots 69in second flange 38; and first ends 46 a and second ends 46 b of springs46 are spaced away from both of contact surfaces 66 a, 66 b of slots 66in first flange 36. Accordingly, with respect to springs 44, in the planview show in FIG. 3 a, contact surfaces 67 a, 67 b of slots 67 arecoincident with contact surfaces 58 a, 58 b of slots 58 and, becauseslots 68 are longer than slots 58, 67, contact surfaces 68 a, 68 b ofslots 68 are positioned circumferentially outside of contact surfaces 67a, 67 b, respectively, of slots 67 and circumferentially outside ofcontact surfaces 58 a, 58 b, respectively, of slots 58. Also, withrespect to springs 46, in the plan view show in FIG. 3 a, contactsurfaces 69 a, 69 b of slots 69 are coincident with contact surfaces 59a, 59 b of slots 59 and, because slots 66 are longer than slots 59, 69,contact surfaces 66 a, 66 b of slots 66 are positioned circumferentiallyoutside of contact surfaces 69 a, 69 b, respectively, of slots 69 andcircumferentially outside of contact surfaces 59 a, 59 b, respectively,of slots 59.

FIG. 3 b shows damper assembly 12 at the end of a first windup stage. Inthe first windup stage, which occurs between the views of FIGS. 3 a and3 b, second flange 38 is rotated clockwise with respect to first flange36 and cover plate 32 in the plan view shown. During the first windupstage, springs 44 work in series with springs 46 at a reduced springrate until one of springs 44, 46 comes into contact with both flanges36, 38. At the end of the first windup stage, each surface 68 a of slots68 in second flange 38 contact the first end 44 a of one of springs 44.The rotation of second flange 38 with respect to first flange 36 andcover plate 32 has also caused each contact surface 69 a of slots 69 insecond flange 38 to move springs 46 such that second end 46 b of eachspring 46 is closer to corresponding contact surface 66 b of slots 66.Additionally, during the first windup stage, the rotation of secondflange 38 with respect to cover plate 32 has caused contact surfaces 69a of slots 69 to move ends 46 a of springs 46 out of contact with thecorresponding contact surfaces 59 a of slots 59 in cover plate 32.Accordingly, with respect to springs 44, in the plan view show in FIG. 3b, contact surfaces 58 a, 68 a of respective slots 58, 67 both contactend 44 a of spring 44 and are coincident and 67 a is spaced away fromend 44 a of spring, while only contact surface 67 b contacts end 44 b ofspring 44, contact surface 58 b is spaced from end 44 b of spring 44 andcontact surface 68 b is spaced further away from end 44 b of spring 44than contact surface 58 b. Also, with respect to springs 46, in the planview show in FIG. 3 b, only contact surface 69 a contacts end 46 a ofspring 46, contact surface 59 a is spaced from end 46 a of spring 46 andcontact surface 66 a is spaced further away from end 46 a of spring 46than contact surface 59 a, while only contact surface 59 b contacts end46 b of spring 46, contact surface 66 b is spaced from end 46 b ofspring 46 and contact surface 69 b is spaced further away from end 46 bof spring 46 further than contact surface 66 b.

FIG. 3 c shows damper assembly 12 at the end of a second windup stage.In the second windup stage, which occurs between the views of FIGS. 3 band 3 c, second flange 38 is rotated further clockwise with respect tofirst flange 36 and cover plate 32 in the plan view shown. The secondwindup stage is the equivalent to the second windup stage of aconventional series damper assembly. This stage only cycles springs 44,via compression by both flanges 36, 38, while springs 46 remains clampedbetween cover plates 32, 34 and flange 38. This continues until thetotal damper travel is equal to the distance between contact surface 68a of slot 68 and end 44 a of spring 44 a_(a)+the distance betweencontact surface 66 b of slot 66 and end 46 b of spring 46 a_(b) (seeFIG. 3 a). It should be noted that if the force required to cyclesprings 44 by a_(a) is equal to the force required to cycle springs 46by a_(b), then the second windup stage is skipped. During the secondwindup stage, the rotational movement of second flange 38 with respectto first flange 36 and cover plate 32 has caused second flange 38 tocompress springs 44, due to the decrease in circumferential distancebetween surface 68 a of each slot 68 and contact surface 67 b of eachslot 67. At the end of the second windup stage, the end 46 b of eachspring 46 has contacted surface 66 b of the corresponding slot 66.Accordingly, with respect to springs 44, in the plan view show in FIG. 3c, contact surfaces 68 a, 58 a of respective slots 68, 58 still contactend 44 a of spring 44 and are coincident and contact surface 67 a ofslot 67 is spaced away from end 44 a of spring 44, while only contactsurface 67 b contacts end 44 b of spring 44, contact surface 58 b isspaced from end 44 b of spring 44 and contact surface 68 b is spacedfurther away from end 44 b of spring 44 than contact surface 58 b. Also,with respect to springs 46, in the plan view show in FIG. 3 c, contactsurface 69 a contacts end 46 a of spring 46, contact surface 59 a isspaced from end 46 a of spring 46 and contact surface 66 a is spacedfurther away from end 46 a of spring 46 than contact surface 59 a, whilecontact surfaces 59 b, 66 b contact end 46 b of spring 46 and arecoincident with each other and contact surface 69 b is spaced away fromend 46 b of spring 46.

FIG. 3 d shows damper assembly 12 at the end of a third windup stage. Inthe third windup stage, which occurs between the views of FIGS. 3 c and3 d, second flange 38 is rotated further clockwise with respect to firstflange 36 and cover plate 32 in the plan view shown. In the third windupstage, the damper reaches the travel of a_(a)+a_(b) and the torque iscalculated both in series and in parallel. The difference between thetorque in series and the torque in parallel determines the force/torquerequired to transition into the third windup stage. During the thirdwindup stage, no force/torque is transmitted through cover plates 32,34, and springs 44, 46 instead contact directly from flange 36 to flange38 in parallel arrangement.

During the third windup stage, the rotational movement of second flange38 with respect to first flange 36 and cover plate 32 has caused secondflange 38 to further compress springs 44, due to a further decrease incircumferential distance between surface 68 a of each slot 68 andcontact surface 67 b of each slot 67. The rotational movement of secondflange 38 with respect to first flange 36 and cover plate 32 during thethird windup stage has also caused second flange 38 to compress springs46, due to the decrease in circumferential distance between surface 69 aof each slot 69 and contact surface 66 b of each slot 66. Additionally,during the third windup stage, the rotation of second flange 38 withrespect to cover plate 32 has caused contact surfaces 68 a of slots 68to move ends 44 a of springs 44 out of contact with the correspondingcontact surface 58 a of cover plate 32. Accordingly, with respect tosprings 44, in the plan view show in FIG. 3 d, only contact surface 68 acontacts end 44 a of spring 44, contact surface 58 a is spaced from end44 a of spring 44 and contact surface 67 a is spaced further away fromend 44 a of spring 44 than contact surface 58 a, while only contactsurface 67 b contacts end 44 b of spring 44, contact surface 58 b isspaced from end 44 b of spring 44 and contact surface 68 b is spacedfurther away from end 44 b of spring 44 than contact surface 58 b. Also,with respect to springs 46, in the plan view show in FIG. 3 d, onlycontact surface 69 a contacts end 46 a of spring 46, contact surface 59a is spaced from end 46 a of spring 46 and contact surface 66 a isspaced further away from end 46 a of spring 46 than contact surface 59a, while only contact surface 66 b contacts end 46 b of spring 46,contact surface 59 b is spaced from end 46 b of spring 46 and contactsurface 69 b is spaced further away from end 46 b of spring 46 thancontact surface 59 b.

FIG. 4 shows a damper assembly 112 in accordance with another embodimentof the present invention. Damper 112 is formed in substantially the samemanner as damper assembly 112, except that springs 44, 46 are used inseries with another set of arc springs 140 and flange 38 is replaced bya flange 138 having a spring retainer 142 formed at a radial outer endthereof. Spring retainer 142 retains arc springs 140. A drive portion150 of a lock up clutch circumferentially engages springs 140. When thisconfiguration is used the preload stage can be eliminated and anotheruseful stage can be added to the damper. In one preferred embodiment,the capacity of the arc springs 140 shown in this design have a capacityequal to the torque required to enter the final stage of the base damperformed by springs 44, 46.

In the preceding specification, the invention has been described withreference to specific exemplary embodiments and examples thereof. Itwill, however, be evident that various modifications and changes may bemade thereto without departing from the broader spirit and scope ofinvention as set forth in the claims that follow. The specification anddrawings are accordingly to be regarded in an illustrative manner ratherthan a restrictive sense.

What is claimed is:
 1. A damper assembly for a torque convertercomprising: a first cover plate; a second cover plate, the first coverplate and second cover plate supporting springs therebetween,; a firstflange between the first cover plate and the second cover plate; and asecond flange between the first cover plate and the second plate, thefirst flange and second flange being arranged with respect to the firstand second cover plates and the springs such that the springs transitionduring operation of the damper assembly from initially operating inseries to operating in parallel.
 2. The damper assembly as recited inclaim 1 wherein the springs are at a same radial distance from a centeraxis of the damper assembly.
 3. The damper assembly as recited in claim1 wherein all of the springs are contacted and compressed by both thefirst flange and the second flange while operating in parallel.
 4. Thedamper assembly as recited in claim 1 wherein the springs include atleast one first spring having a first end held by the first flange and asecond end held by at least one of the first cover plate and the secondcover plate in a 0° windup condition, the springs including at least onesecond spring having a first end held by the second flange and a secondend held by the at least one of the first cover plate and the secondcover plate in a 0° windup condition.
 5. The damper assembly as recitedin claim 4 wherein at the end of a first windup stage, the second flangecontacts the second end of the at least one first spring.
 6. The damperassembly as recited in claim 5 wherein the second flange moves the atleast one second spring circumferentially towards the first flangebetween the 0° windup condition and the end of the first windup stage.7. The damper assembly as recited in claim 5 wherein at the end of asecond windup stage, the first flange contacts the second end of the atleast one second spring.
 8. The damper assembly as recited in claim 7wherein the second flange compresses the at least one first springbetween the end of the first windup stage and the end of the secondwindup stage.
 9. The damper assembly as recited in claim 7 wherein atthe end of a third windup stage, the second flange holds the second endof the at least one first spring circumferentially away from the atleast one of the first cover plate and the second cover.
 10. The damperassembly as recited in claim 9 wherein the first flange and the secondflange further compress the at least one first spring between the end ofthe second windup stage and the end of the third windup stage.
 11. Thedamper assembly as recited in claim 9 wherein at the end of the thirdwindup stage, the first flange holds the second end of the at least onesecond spring circumferentially away from the at least one of the firstcover plate and the second cover plate.
 12. The damper assembly asrecited in claim 11 wherein the first flange and the second flangecompress the at least one second spring between the end of the secondwindup stage and the end of the third windup stage.
 13. The damperassembly as recited in claim 1 wherein the first flange includes atleast one first slot of a first length and at least one second slot of asecond length greater than the first length, one of the springs beingreceived in the first slot in the first flange and one of the springsbeing received in the second slot in the first flange.
 14. The damperassembly as recited in claim 13 wherein the second flange includes atleast one third slot of a third length and at least one fourth slot of afourth length, one of the springs being received in the third slot inthe second flange and one of the springs being received in the fourthslot in the second flange.
 15. The damper assembly as recited in 14wherein the spring received in the first slot is also received in thefourth slot.
 16. The damper assembly as recited in claim 15 wherein thespring received in the second slot is also received in the third slot.17. The damper assembly as recited in claim 1 wherein the torque isinput through one of the first flange and the second flange and outputthrough the other of the first flange and the second flange.
 18. Atorque converter for a motor vehicle drive train comprising: the damperassembly as recited in claim 1; and a turbine connected to the damperassembly.
 19. The torque converter as recited in claim 18 furthercomprising a lockup clutch rotationally coupled to the damper assembly.20. The torque converter as recited in claim 19 wherein the lockupclutch includes a piston, the piston being rotationally connected to thesecond flange.